On June 12, 2025, Air India flight crashed shortly after takeoff, killing 260 people. The plane carried 33,000 gallons (125,000 liters) of fuel, leading to a massive fire, with some bodies burning beyond recognition, fragmented or unrecognized. To identify the remains, authorities sought DNA samples from the victim’s family. More than two weeks after the disaster, completed DNA analysis successfully identified all those lost in the crash.
Around the world, DNA analysis is the gold standard for identifying human remains following mass disasters of these types, whether it is a transport accident such as Air India collisions, major natural disasters, or terrorist attacks. But how does DNA analysis actually work? And how does it help identify victims in these tragic events, including mass lethality?
DNA analysis involves collection of two types of samples. It’s a postmaltem and antemotem. Other experts take photos of the victim’s teeth, and police officers collect fingerprints and pay attention to certain attributes such as clothing and personal belongings, post-mortem DNA is collected on site, said Kelstin Monterius, a molecular biologist with the Swedish National Committee of Forensic Medicine.
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“DNA samples can come from any tissue in the body,” Monterius told Live Science in an email. “DNA samples are sent to the lab where DNA is extracted from the tissue.”
Those collecting DNA should ensure that the sample is not contaminated given the high risk of human remains mixing after a mass disaster. The environment can also compromise the quality of the samples. For example, victims of the World Trade Center attack on September 11 were exposed to severe fires, heat and fire extinguishing water, and in 2004 victims of the Southeast Asian tsunami were exposed to seawater and warm, humid air.
To minimize contamination, blood or intact soft tissue samples are usually recommended for analysis. The exception is when sites where bone and tooth samples are preferred are decay or mixed, according to a 2007 paper on minimizing the risk of contamination published in Journal Forensic Science, Medicine, and Pathology.
Related: How does DNA test tell you whether two people are related?
“If the effect of accurate environmental factors is uncertain, it appears wise to collect different types of tissue samples from each victim,” the paper states.
The next step is to prepare the DNA profile for each victim. This involves washing and separating the DNA from the tissue sample, determining the approximate amount of DNA present, and copying that DNA using enzymes. Finally, DNA fragments are separated based on size, and the individual’s DNA is visually expressed.
“The recovered DNA profiles are compared to samples of Antemortem, namely items known to belong to victims such as toothbrushes and razors,” Watherson told Live Science in an email. “Alternatively, the recovered DNA profiles are compared to samples recovered from known biological relatives (e.g., the mother or father of the victim.”
When carried out to the expected high levels, this DNA analysis is an innocent method and, when combined with other types of chemical analysis, can even be used to distinguish identical twins, said Peter Ellis, an Australian forensic pathologist who chairs a subgroup of Interpol’s Disaster Victim Identification Labor Group. That said, the process poses several challenges, he told Live Science in an email.
“Occasional drawbacks include the technical equipment needed to implement it. [and] The need for good [postmortem] Ellis said that the undegraded samples “may not contain enough DNA to allow for identification.”
While DNA analysis is an important scientific tool for identifying victims of mass disasters, the process includes many ethical questions, such as “assumptions about where and how identity is located, how the body is treated after death, and how disasters are managed.”
Bennett wrote a paper on how the DNA analysis process contradicts sociopolitical and cultural norms. Quoting the Iraq example in 2005, the government “supposed physical integrity” for those who went missing during Saddam Hussein’s Baassist regime. The Iraqi government also claimed that bone sections collected for DNA analysis will be returned to the body for burial.
“It’s important to consider such questions before you begin the process,” Bennett told Live Science in an email.
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